Note:ERI's are an exception to a valid chain starting spot it can be used only if the center cell is absent as this leaves either the row or col true, the * cell is used as a pivot between row/col

Weak Links exists in cells that are part of a strong link set, that see parts of another strong link sets without being part of it, or directly seeing all of it. 0,0). Bivalve that sees another bivalve with digit shared